From cf8414dca50dd3994703786af3b7944d9b917dc9 Mon Sep 17 00:00:00 2001 From: Rudolf Cornelissen Date: Tue, 11 Apr 2006 11:28:25 +0000 Subject: [PATCH] updated docs again. Forgot to mention AGP transfers are used these days for nVidia graphics card ownners (both 2D and 3D :) git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17072 a95241bf-73f2-0310-859d-f6bbb57e9c96 --- src/add-ons/kernel/bus_managers/agp/README.html | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/add-ons/kernel/bus_managers/agp/README.html b/src/add-ons/kernel/bus_managers/agp/README.html index 42ceae485b..297b168cf8 100644 --- a/src/add-ons/kernel/bus_managers/agp/README.html +++ b/src/add-ons/kernel/bus_managers/agp/README.html @@ -75,15 +75,15 @@ This option is disabled by default (preceded by a '#').
If set to 'true' this option blocks use of AGP transfers entirely including PCI fastwrites: so fallback to standard 'old-fashioned' PCI mode.
  • block_sba: (set to 'false' by default)
    If set to 'true' this option blocks use of sideband adressing if at least one of the devices on the bus is pre-AGP3.0. Sideband adressing speeds up AGP transfers a bit because it's a seperate (low-speed) communications 'channel' that's used alongside the main transfer channel concurrently. So this enables 'full-duplex' communications, while disabling SBA forces the hardware to use 'half-duplex' communications. SBA is a requirement for AGP3 compliance, so if AGP3 is in effect, this setting is ignored. -
  • block_fw: (set to 'false' by default)
    - If set to 'true' this option blocks use of PCI fastwrites. PCI fastwrites work in the same speed AGP transfers work. This means PCI fastwrites are faster in AGP4x mode than they are in AGP2x mode (for instance). PCI fastwrites are used whenever the system initiates transfers to the graphicscard, while 'standard PCI' or AGP transfers are used if the graphicscard's acceleration engine initiates transfers to or from the system.
    -This means that PCI FW is the only AGP 'feature' that has an effect on the graphics speed on BeOS as it is currently. The use of AGP transfers require graphicsdriver support, and these type of transfers are 'officially' targeted specific for hardware accelerated 3D (which we do not yet have).
    +
  • block_fw: (set to 'true' by default)
    + If set to 'true' this option blocks use of PCI fastwrites. PCI fastwrites work in the same speed AGP transfers work. This means PCI fastwrites are faster in AGP4x mode than they are in AGP2x mode (for instance). PCI fastwrites are used whenever the system (CPU) initiates transfers to the graphicscard, while 'standard PCI' or AGP transfers are used if the graphicscard's acceleration engine (GPU) initiates transfers to or from the system respectively.
    +This means that PCI FW is the only AGP 'feature' that has an effect on the graphics speed on BeOS as it is currently, except for users of the nVidia driver(s). The use of AGP transfers require graphicsdriver support, which is built-in inside the 2D and 3D nVidia drivers. Note please that PCI fastwrites might still be used for texture loading for accelerated 3D...
    Note:
    PCI FW support was first introduced with the AGP2.0 specification: that is, devices that support upto and including AGP4X mode are candidates to have this feature.

    Rudolf Cornelissen. -

    (Page last updated on July 19, 2004)

    +

    (Page last updated on April 11, 2006)